feat(other): add documentation check to CI

.github/file-filters.yml

@@ -11,3 +11,6 @@ webapp: &webapp
   - '.github/workflows/test-webapp.yml'
   - 'webapp/**/*'
   - 'package.json'
+
+markdown-files: &markdown-files
+  - '**/*.md'

.github/workflows/check-documentation.yml

@@ -0,0 +1,40 @@
+name: ocelot.social check documentation
+
+on: push
+
+jobs:
+  files-changed:
+    name: Detect File Changes - Markdown files
+    runs-on: ubuntu-latest
+    outputs:
+      markdown-files: ${{ steps.changes.outputs.markdown-files }}
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@master
+
+      - name: Check for markdown file changes
+        uses: dorny/paths-filter@v2.11.1
+        id: changes
+        with:
+          token: ${{ github.token }}
+          filters: .github/file-filters.yml
+          list-files: shell
+
+  check-markdown-links:
+    name: Check Markdown links
+    if: needs.files-changed.outputs.markdown-files == 'true'
+    needs: files-changed
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@master
+    - name: Check Markdown Links
+      uses: gaurav-nelson/github-action-markdown-link-check@master
+      with:
+        use-quiet-mode: 'yes'
+        use-verbose-mode: 'no'
+        # at any .md file change take the chance to check the links in all .md files
+        check-modified-files-only: 'no'
+        config-file: '.github/workflows/mlc_config.json'
+        base-branch: 'master'
+        folder-path: '.'

.github/workflows/mlc_config.json

@@ -0,0 +1,12 @@
+{
+  "timeout": "20s",
+  "retryOn429": true,
+  "retryCount": 2,
+  "fallbackRetryDelay": "30s",
+  "aliveStatusCodes": [200, 206],
+  "ignorePatterns": [
+    {
+      "pattern": "^(https:\/\/github.com\/Ocelot-Social-Community\/Ocelot-Social\/pull\/|http:\/\/localhost)"
+    }
+  ]
+}